So, how to locate C:?
Go to CrossOver's Manage Bottles window. You'll find it in the Configure menu. Select the bottle (left panel) and click the Advanced tab. Below the big picture of the wine bottle you'll find a button labelled Open C: Drive in Finder. Click this.
Finder now shows you a folder called drive_c. This corresponds to the C: drive when Windows applications run in the bottle. Anything you copy here will appear in C: when a Windows program runs.
With Watchtower Library or Reader installed, you notice a folder called Program Files, and beneath that another sub-folder called Watchtower. (Of course, you'll find exactly the same sub-directory arrangement on Microsoft Windows!)
Underneath Watchtower, you'll see a number of sub-folders. The following "tree" summarises the structure, showing folders only though you'll also find various files.
Program Files Watchtower MEPSCommon Watchtower Reader E rs_data
The E folder contains English publications. Notice rs_data. Replace this folder from the 2007 edition CD by directly copying it. Don't install the 2007 library application. Just drag and drop rs_data from CD to the E folder. Finder asks if you want to replace the existing rs_data (from 2006 CD). Say yes.
Note, if you do not get the replace confirmation then you likely copied it to the wrong place!
Regards, Roy